Background and Aims: Animal models have been demonstrating that MMPs have an important function in the tooth eruption process. The aim of this study was to evaluate the association between genetic polymorphisms in MMP8 and MMP13 and delayed tooth eruption of permanent teeth. Materials and Methods: This cross-sectional study selected 216 children, 9- to 12-year-old, from public schools at Manaus, Amazonas, Brazil. During oral clinical examination, each permanent tooth emerged in the oral cavity was evaluated. Children were considered with delayed tooth eruption when at least one permanent tooth was delayed and were classified in 2 groups: children “with delayed tooth emergency” and “without delayed tooth emergency.” Saliva samples were collected from DNA extraction. The genetic polymorphisms rs17099443 and rs3765620 in MMP8, and rs478927 and rs2252070 in MMP13 were genotyped. Statistical Analysis: PLINK V1.07 ( http://pngu.mgh.harvard.edu/purcell/plink/ ) and GraphPad Prism 5.0 (San Diego, CA, USA) were used. The c² or Fisher exact test was used to calculate genotypes and alleles distributions. To compare the mean number of delayed teeth according to genotypes, the Kruskal-Wallis test with multiple comparison Dunn test was used. The established alpha for all comparisons was .05. Results: The polymorphism rs17099443 in MMP8 was associated with delayed tooth eruption in the genotype distribution ( P = .05). In the allele distribution, the C allele was underrepresented in children with delayed tooth eruption ( P = .01; OR = 0.61, 95% confidence interval, 0.41–0.9). Conclusion: The genetic polymorphism rs17099443 in MMP8 is associated with delayed tooth eruption.